With "this particular spelling" you mean
Rhea but without h? Such minor variants in spelling normally do not have a separate identifiable history, so that you could say e.g. "Rea in constrast to
Rhea only became popular because of ..." or "became popular in the 17th century, first in ... and then in ...".
As the post of Miss
Claire already indicates, certainly a spelling variant does not give a different meaning.
Articles like this one:
http://en.wikipedia.org/wiki/Rhea_Silviashow that Rea as a form must be pretty old.
Rene www.AboutNames.ch